• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.241-252
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• 1992

The purpose of this study was to investigate the changes of morphology and structure of bone tissue in the irradiated mandibular bone in rats which were fed a low calcium diet. In order to carry out this experimant, 64 seven-week old Sprague-Dawley strain rats weighing about 150gms were selected and equally divided into one experimental group of 32 rats and one control group with the remainder. The experimental group and the control group were then subdivided into two groups when the rats reached ten-week old, 16 were assigned rats for each subdivided group, exposed to irradiation. The two irradiation groups received a single dose of 20 Gy in the jaws area only and irradiated with a cobalt-60 teletherapy unit. The rats in the control and experimental groups were serially terminated by fours on the 3rd, the 7th, the 14th, and the 21st day after irradiation. Following termination, both sides of the dead rats mandibular bodies were removed and fixed with 10% neutral formalin. One side of the mandibular body was radiographed with a soft X-ray apparatus. Thereafter, the obtained microradiographs were observed by a light microscope. The remaining side of the mandibular bone was further decalcified and embedded in paraffin as using the general method. The specimen sectioned and stained with hematoxylin and eosin, and Rabit Anti-Human Tumor Necrosis Factor-a, observed by a light microscope. The obtained results were as follows: 1. Microradiogram revealed that thinning of the cortex and a decrease in the trabecula of the interradicular bone and mandibular body were observed and noted from the start to finish throughout the experiment in the non-irradiated rats on the low calcium diet rather than in the non-irradiated rats on the normal diet. In microscopic observations, there were marked osteolytic changes in the center of the bone marrow. 2. Microradiogram revealed that thinning of the cortex and a decrease in the trabecula of interradicular bone and mandibular body were more marked after 7 days in the irradiated rats on the low calcium diet rather than in the non-irradiated rats on the low clacium diet. In microscopic observations, osteoblasts were decreased markedly after 7 days, and a few osteoclasts were observed. 3. Microradiogram revealed that thinning of the cortex and a decrease in trabecula of interradicular bone and the mandibular body were more marked from the strart to finish troughout the experiment in the irradiated rats on the low calcium diet rather than in the irradiated rats on the normal diet. In microscopic observations, there were no osteolytic changes noted in the irradiated rats on the normal diet. 4. In immunocytochemical findings, a few bone marrow cells including Tumor Necrosis Factor were observed in the irradiated rats on the normal diet, but was not observed in the rats on the low calcium diet.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.2 s.120
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• pp.31-37
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• 2007

Lithography like off-set printing is processed using the repellent properties between water and oil, so all inks for off-printing must work with dampening solution(water). The dampening water may cause the emulsification of ink by the printing pressure in the printing nip. This study aimed to investigate the effect of emulsified inks on print mottle. The cyan ink was emulsified artificially with the different IPA(isopropyl alcohol) content in this study. We evaluated the print mottle by densitometer and image analysis method. The print mottle phenomenon was directly affected by IPA content. The emulsification of inks also had an influence on flow properties of inks and it increased ink transfer rate. It, however, caused low ink density. Moreover the emulsified inks were spreaded to around dots and cause the thinning density on the non-printing area like print mottle. The trial printing showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. We could, therefore, find out the obvious effect of emulsified inks on print mottle.

• Journal of Bio-Environment Control
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• v.23 no.3
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• pp.205-211
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• 2014

This study aimed to examine the effect of different fruit-loads on fruit yield, quality, and plant growth of 'Seolhyang' strawberry. Fruit loads were adjusted from the first to the fourth flower cluster so that the number of fruits became 20, 25, and 30, and non-flower thinning of some was made. The more the number of fruits per plant was, the greater the total yield obtained, but marketable yield decreased and non-marketable yield increased. Compared to the treatment whose fruit load was adjusted, the control with non-flower thinning had more fruit yield in the first and second flower clusters but tended to have less fruit yield in the third and fourth flower clusters. The lower the fruit load was, the more soluble solids content of fruits increased. The lower the fruit load of a flower cluster was, the faster its harvest time reached. Harvest of fruit load of 20 was faster by 10 days in the second and fourth flower clusters relative to the control. On November 24, 2012, flowering thinning of the first flower cluster was made. On March 7, 2013, fruit dry weight of the second flower cluster was most heavy in the control. Dry weight of roots decreased in the control and the fruit load of 30 compared to November 24. On April 9, fruit dry weight of the third flower cluster did not have significant difference according to fruit load, however the more the fruit load was, the smaller dry weight of leaf, root, and crown became, which were vegetative organs. On May 12, the more the fruit load, the smaller leaf area and dry weight of vegetative organs and differences from varying fruit-loads became considerable in later period of growth. Appropriate fruit load of 'Seolhyang' strawberry were from 20 to 25. Maintaining balance between vegetative and fruit growth by adjusting fruit load is very important for stable fruit production.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.227-235
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• 2000

Agricultural products are easily deformable its shape because of some external forces. However, these force behavior is difficult to measure quantitatively. Until now, many researches on the mechanical property was performed with various methods such as material testing, chemical analysis and non-destructive methods. In order to investigate force behavior on the cellular unit of agricultural products, electro-microscope based 3D image processing method will contribute to analysis of plant cells behavior. Before image measurement of plant cells, plant sample was cut off cross-sectioned area in a size of almost 300-400 ${\mu}$ m units using the micron thickness device, and some of preprocessing procedure was performed with fixing and dyeing. However, the wall structure of plant cell is closely neighbor each other, it is necessary to separate its boundary pixel. Therefore, image merging and shrinking algorithm was adopted to avoid disconnection. After then, boundary pixel was traced through thinning algorithm. Each image from the electro-microscope has a information of x,y position and its height along the z axis cross sectioned image plane. 3D image was constructed using the continuous image combination. Major feature was acquired from a fault image and measured area, thickness of cell wall, shape and unit cell volume. The shape of plant cell was consist of multiple facet shape. Through this measured information, it is possible to construct for structure shape of unit plant cell. This micro unit image processing techniques will contribute to the filed of agricultural mechanical property and will use to construct unit cell model of each agricultural products and information of boundary will use for finite element analysis on unit cell image.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.47-52
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• 2011

An electromagnetic acoustic transducer(EMAT) is a non-contact transducer which can transmit the ultrasonic guided waves into specimens without couplant. And it can easily generate specific guided waves such as SH(shear horizontal) or Lamb waves by altering the design of coil and magnet. In this study, the SH wave, which is generated by EMAT, has been applied to estimate the thickness-reduction in a steel plate. Especially, the interesting feature of the dispersive behavior in selected wave modes is used to detect the thickness-reduction. Experimental results show that the reduction-level can be quantified by the measurement of the group velocity of the wave which passes though the thinning area.

• Journal of the Korean Society of Radiology
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• v.2 no.1
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• pp.23-29
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• 2008

The present study proposed a method that dissolves ultrasonographic images into multiple resolutions using wavelet conversion and a boundary detection filter and improves the quality of ultrasonographic images through boundary detection filtering. In order to reduce noises and strengthen edges, the proposed method adjusted selectivity coefficient by area step by step from a low resolution image obtained from wavelet converted images to a high resolution image and performed edge filtering in consideration of direction. Through this method, we generated a selective low pass filtering effect in areas except edges by decreasing the wavelet coefficient for pixels in spot areas, improved continuity by smoothing edges in the tangential direction, and enhanced contrast by thinning in the normal direction. Through an experiment, we compared the filtering method using a non linear anisotropic expansion model and the filtering method using wavelet contraction structure in single resolution.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.2
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• pp.1-13
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• 2008

Printed mottle of coated paper is one of the most common phenomenon and the most difficult problem in offset printing. Offset printing is processed mainly processed by the attractive properties between water and oil, so all inks for off-printing must work with dampening solution(water). It may cause the emulsion on the printing nip from the printing pressure. This study aimed to investigate the effect of emulsified inks on print mottle from emulsified cyan ink by force with each different IP A contents. We measured the print mottle by densitometer and image analysis method. The emulsified inks also give effect to now properties of inks and it caused more ink transfer rate, however, it caused low density of inks. Moreover the emulsified inks were spreaded to around of dots and cause the thinning density on the non-printing area like print mottle. The results showed that the emulsified inks also cause scumming on the printing result with little mistake of adjusting dampening solution and mostly decreasing dot reproduction. So we could find out the obvious effect of emulsified inks to print mottle.

• Transactions of Materials Processing
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• v.25 no.6
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• pp.379-389
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• 2016

As a stator for steam turbine diaphragm, hollow-type nozzle stator to substitute for conventional solid one is introduced in this study. This hollowed stator can be separated into two parts such as upper and lower plates with large and curved surface area. This study focuses on thick plate forming process for the upper plate of the hollow-partitioned nozzle stator. First, to reduce forming defects such as under-cut and localized thinning of the deformed plate, and to avoid tool interruption between forming punch and lower die, tool design including the position determination of forming surfaces is performed. Uni-axial tensile tests are carried out using SUS409L steel plate with initial thickness of 5.00mm, and plastic strain ratio (r-value) is also obtained. Due to the asymmetric curved configuration of the upper plate, it is hard to adopt a series of blank holder or draw-bead, so the initial plate during this thick plate forming experiences unstable and non-uniform contact. To easy this forming difficulty and find suitable tool geometry without sliding behavior of the workpiece in the die cavity, two geometric parameters with respect to each shoulder angle of the lower die and the upper punch are adopted. FE models with consideration of 21 combinations for the geometric parameters are built-up, and numerical simulations are performed. From the simulated and predicted results, it is shown that the geometric parameter combinations with ($30^{\circ}$, $90^{\circ}$) and ($45^{\circ}$, $90^{\circ}$) for the shoulder angle of the lower die and the upper punch are suitably applied to this upper plate forming of the hollow-partitioned nozzle stator used for the turbine diaphragm.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.649-653
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• 2001

The Chiari malformation is a deformation within the central nervous system which the lower brain stem and the cerebellum migrate into the foramen magnum causing herniation. In 1891, Arnold Chiari classified such symptoms into 3 categories. This case report is of a 8-year-old female with the complaint of a slight facial swelling and pain on the upper right molar during tooth brushing since 10 days before. Clinical examination showed gingival pocket formation on distal of the upper right first molar with pain and mobility of the tooth. Radiographic examination showed generalized low bone density in the upper molar area, and especially no bone support above the upper right and left first molars were noted. With a temporary diagnosis of Early-onset periodontitis, consultations with medical doctors for the possibility of an underlying systemic disease were made during periodontal treatment. 3D CT was taken with after a final diagnosis of Chiari malformation. Generalized thinning and defect of the cranial bone was noted and the foramen magnum was slightly enlarged. The occipital and maxillary bone was low in density, and the alveolar bone of maxillary posterior teeth was especially almost non-existing causing the upper right and left first molar to be floating. For this, the patient went under consultation with the department of neurosurgery and is still under observation. Periodontitis in childreren is very rare. When symptoms of periodontitis appear in a child, due to the possibility of an underlying systemic disease such as leukemia, histiocytosis X, and hypophosphatasia, proper examinations should be carried out so that the primary factor the symptoms can be treated.